Refrigeration



@JamI Z, 1942. H, M, uLLs-rRAND 2,285,131

REFRIGERA'mN Fildd March' 14, 1938 www i 4 ATTORNEY Patented June 2, 1942 REFRIGEBATION Hugo M. Ullstrand, Evansville, Ind., assignor to Servel, Ine., New York,

Delaware N. Y., a corporation of Application March 14, 1938, Serial No. 195,736

12 Claims.

'I'his invention relates to refrigeration, and it is an object of the invention to provide an improvement for transferring heat whereby cooling is effected at a higher level than a source of refrigeration;

The above and other objects and advantages y of the invention will become apparent from the following description taken in `conjunction with the' accompanying drawing forming a part of this specification, and of which the single figure more or less diagrammatically illustrates an embodiment of the invention.

, In the drawing the invention is shown in connection with a cooling element or evaporator I of a refrigeration system of a uniform pressure absorption type, and like that described in application Serial No. 107,852 of A. R. Thomas, led,

October 27, 1936-, now Patent No. 2,207,838 granted July 16, 1940. The cooling element II) includes a casing I I which may be embedded in insulation I2. -Liquid refrigerant, such as ammonia, enters the upper part of casing II through a vconduit I4. 'Ihe liquid evaporates and diffuses in casing I I into an inert gas, such as hydrogen, to produce a refrigerating eii'ect. 'I'he resulting gas mixture of refrigerant an inert gas ows from casing II through a conduit I to an absorber wherein refrigerant gas is absorbed into a liquid absorbent, such as water. Inert gas weak in refrigerant is returned to cooling element I0 through 'a conduit I6 and a cylinder I1 which is disposed within casing II and open at its upper end.

Absorption liquid which is enriched in the absorber is conducted to a generator where it is heated and` refrigerant is expelled out of solution.

Refrigerant vapor expelled out of solutionis con-A densed in a condenser and then returned to cooling element l0 through conduit I4 to complete the refrigerating cycle. The weakened absorption liquid from which refrigerant has been expelled is conducted from the generator to the absorber to again `absorb refrigerant vapor.

In order to simplify the drawing, the absorber, generator, and condenser of the refrigeration system have not been shown, the illustration of these parts not being necessary for an understanding' of this invention. The disclosurefin the aforeranged about cylinder l1 and over which liquid refrigerant flows. The coil I8 constitutes the condenser of a heat transfer system whereby cooling may be effected at a place above the cooling element I0. The heat transfer system includes an evaporator I9 which is of the flooded type and located at a higher level than condenser I8, The evaporator I9 is disposed in a heat insulated space 20 and includes a receiver 2| having a looped coil 22 connected thereto. A plurality of heat transfer fins 23 are fixed to coil 22 to increase the fheat transfer surface of the evaporator. y

The condenser I8 and evaporator I9 form part of a closed .fluid circuit which is partly filled with a suitable volatile liquid, such as methyl chloride, for example, that Aevaporatesl in evaporator I9 and takes up heat thereby producing cold. The vapor flows from evaporator I9 through a conduit; 24 into condenser I8 inl which the vapor is cooled and condensed by cooling element I0.

In accordance with the invention, a transfer vessel 25 is provided for raising liquid from condenser I8 to evaporator I9 so that cooling may be effected in space 2U. The transfer vessel 25 comprises a casing26 divided into two chambers 21 and 28 by a partition 29. The lower end of condenser I8.is connected by a U-shaped conduit 30 to the upper part of chamber 21.

A check valve 3l may be connected in conduit 30. The lowerepart of chamber 28 is connected by a conduit 32 to an upper part of receiver 2I mentioned Thomas application may be considered as being incorporated in this application, and, if desired, reference may be made thereto for a more detailed description of the refrigeration system.

The refrigerating effect produced by cooling element I0 is utilized to cool and liquefy a vvola.-

tween the upper parts of chambers 21 and 28.

The operation of the heat transfer system just described is substantially .as follows: The vapor formed in evaporator I9 flows `through conduit 24 into condenser I8 in which the vapor is condensed, as explained above. The condensed uid iiows from condenser I3 through conduit 30 into f upper chamber 21 of transfer vessel 25. The check valve 3| permits f iow of liquid into chamber 21 due to the liquid head in the left-hand leg of conduit 30. During the periods when liquid is owing into upper chamber 21, the lower chamtile iiuid flowing through a coil I8 which is ar- 5 5 ber 28 and conduit 32 are empty and these parts,

together with tube 35, provide a vent for upper chamber 21.

When the liquid level inchamber 21 rises to the upper end of syphon tube 34, the liquid in the upper chamber is syphoned through tube 34 into lower chamber 28. 'I 'he liquid nowing into lower chamber 28 forms a liquid column in this chamber and in the lower part/of conduit 32. The flow of liquid from upper. chamber 21 into lower chamber -28 stops when the liquid level falls .below the lowerend of tube 34 in upper chamber 21.

The liquid segregated in lower chamber' 28 evaporates dueto heat transfer from surroundelevation, raising liquid condensate between said ing warmer air which may -be at room tempera.-

ture. The vapor formed in this manner may flow into upper chamber'21 through vent tube 35. The vaporpressure above the liquid in lower chamber 28 and also in upper chamber 21 continues to increase, due to evaporation of liquid, and acts to close check valve 3 I. When the vapor pressure is suiliciently great, liquid is forced upwardlyin conduit 32 and into receiver 2I. All of the segregated liquid is raised into receiver 21 whereby the trapped vapor is also released into receiver 2i. When trapped vapor is released into receiver 2I, lower chamber 28 and conduit 32 do not contain any liquid.

With transfer vessel 25 and evaporator I9 again in open communication with eachI other, the pressure in the system becomes equalized,

and, with the liquidI head in the left-hand leg of conduit `ill! sufficiently "high,` check valve 3l is opened and liquid flows into upperchamber 21. When the-liquid level in upper chamber 21 rises to the upper end of syphon tube 34, liquid ilows from upper chamber 21 into lower chamber 28 and a pressure difference is again produced orf created between transfer vessel 25`and evapora-` tor I9, due to the temperature difference of these parts.

If the height of 'the liquid trap vformed by f U-shaped conduit 30 is sufficiently long, check valve 3| may be omitted. In such case liquid in the right-hand leg of U-shaped 4conduit 30 is forced downward when the vapor pressure 4builds up in chambers 21 and 28 to force liquid upward from chamber 28-to evaporator I9. The height of the liquid trap should be greater than the height through'which liquid is raised in conduit 32, so that the liquid column in the left-hand leg of U-shaped conduit 38 will always balance the vapor pressure in chambers 21 and 28.

elevations by removing a quantity of said accumulated liquid at intermittent intervals of time, lifting substantially all of the removed liquid by trapping vapor vabove a liquid surface thereof to produce a lifting force, and alternately trapping vapor above the removed liquid and releasing the vapor after substantially all of the removed liquid has been raised.

3. A method as defined in claim 2 in which the ytrapped. vapor is formed by transfer. of heat to the removed liquid.

4. A method as defined in claim 2 in which the trapped vapor `isformed by atmospheric heating of the removed liquid.

5. A method as defined in claim 2 in which the trapped vapor is released in the place of vaporization. A

6. A heat transfer system comprising a closed fluid circuit partly filled with a volatile liquid and includingja vaporization portion atan upper elevation and a condensation portion at a lower elevation, thermally insulated means to accumulate liquid condensed at' said lower level, and means to raise `liquid between said elevations and including structure to remove a quantity of said accumulated liquid at intermittent intervals of time vand accumulate vapor above a liquid surface thereof to exert a lifting force to lift substantially all of theA removed liquid, and said structure being constructed and arranged to permit release of accumulated vapor therefrom when substantially all of the removed liquid-has been lifted.

L- 7 A heat transfer system as defined in claim 6 and `including a conduit to permit release of ac- With the liquid trap sulciently long, trapped vapor will always be released to evaporator I9 lin conduit 38 will flow from condenser I8 into upper chamber 21 of the transferchamber.`

While a single embodiment of `the invention has been shown and described, suchvariations cumulated vapor to said vaporization portion.

8. A heat 'transfer system ask defined in claim 6 in which accumulated vapor is formedby atmospheric heating of removed liquid.

9. A heat transfer system as dened in claim having means to prevent flow of liquid to said A high value.

and modifications are contemplated which fall` within the true spirit and scopeof the invention;

as, pointed out in the following claims'.

l'l. A method of heat transfer which includes vaporizing liquid fluid in a .place of vaporization at an upper-elevation, condensing vaporized fluid V in a place of condensation at a lower elevation', accumulating the liquid condensed at said lower elevation, raising liquid condensate between said elevations-by segregating a quantity of said accumulated liquid at'intermittent intervals of time by siphonic action, lifting substantially all of the segregated liquid by trapping vapor above .a liquid surface thereof ,to produce a force thereon and alternately trappingvapor above the segregated liquid and releasing the vapor after substantially all of the segregated liquid has been vationvand a condensation portion at a lower elevation, thermally insulated lmeans to accumulate liquid condensed at said lower elevation, and

means to raise liquid between said elevations and including a. si'phon to segregate a quantity of said v5.

accumulated liquid at intermittent intervals of time, and structure to accumulate vapor above 

